Diet Dilemma

August 22, 2002|By Marian Burros New York Times News Service

Every 10 years or so, it seems, the nation's anxiety over dieting builds to a peak and a realization hits home: Whatever weight-loss program has so recently captivated us is wrong. Fat might be good for us now, some people say, and carbohydrates bad. Not so long ago, the opposite was true. Probably it will be again. These things tend to work as pendulums do.

Diet fads and government guidelines over the last quarter century have not helped to produce a slimmer America. We are a fatter nation now, on average, than we were in the 1970s. What diet fads have given us are short-term losses and long-term gains because few if any of them emphasize a key fact: If you consume more calories than you expend, you will gain weight. Despite what the opposing sides in this long-running debate assert, it doesn't make much difference where the calories come from. A successful dieter needs to burn them.

At the two poles of the current debate over diet are the protein- and fat-rich Atkins diet and the high-fiber, low-fat program put forward by Dr. Dean Ornish. In the middle sits the Agriculture Department's Food Guide Pyramid, which tells consumers to reduce fats, but allows them to increase carbohydrates significantly.

The Atkins diet doesn't seem to restrict calories. In fact it does. The diet makes it difficult to eat as many calories as one gets from the carbohydrates that contain no fiber: sugar, white flour, pasta and the like. Filled with steak, in other words, you're simply too "full" to eat dessert.

The Ornish diet is at the other extreme, saying you can eat all you want, but only of foods very low in fat and very high in fiber, making it a low-calorie diet because fiber acts like fat. It fills you up.

It all seems very simple: Eat fat and protein (Atkins) and a process takes place that most of us don't understand, and you lose weight. Barely eat any fat and stick to complex carbohydrates and the weight will pour off (Ornish).

In both cases it will, at least for the short term; there are no studies to show whether the Atkins diet, in particular, is safe over a lifetime.

Ornish's diet is designed mainly for people who have clogged arteries or have had heart attacks. Using his strict regimen, some of these people have been able to reverse the course of heart disease. Whether the diet is the most desirable for people who are simply overweight has not been determined. There are no lifetime studies.

Caught directly between these two diet extremes is the Food Guide Pyramid, which tells us that fat should be reduced to 30 percent of calories consumed, and that carbohydrates should be increased significantly. It does not, however, distinguish clearly enough between complex carbohydrates like whole grains, fruits and vegetables and refined ones like sugar. Refined carbohydrates turn into blood glucose quite quickly, which in turn drives up insulin production, which lowers blood sugar and -- guess what? -- makes us hungry again. The result is one of unintended consequences.

Since the late 1980s this government-approved diet appears to have provided people with permission to eat as many carbohydrates as they want, no matter the source. And many have.

Over the past 10 or 15 years people not only have continued to consume the same amount of fat but they have also added 200 to 400 calories more a day from carbohydrates. The result is what experts are describing as an epidemic of obesity.

The Agriculture Department is in an untenable position. With the two hats that it wears -- one to protect consumer health and the other to help farmers sell food -- it cannot tell us to eat fewer calories. That would fly in the face of its mandate to help farmers.

There is another unintended consequence of the government's advice. "The pyramid is designed for the food industry," says Dr. Marion Nestle, chair of the department of nutrition and food studies at New York University and author of Food Politics: How the Food Industry Influences Nutrition and Health.

"They knew exactly what to do with it. They said, `You want us to sell foods that are low fat or no fat? Sure, but you didn't say anything about calories!' And so the calories remained the same."

Remember Snackwells, the wildly popular cookie of the 1990s? It had no fat but plenty of refined carbohydrates. The "no fat" label made many people think it was all right to eat an entire box. In one sitting. No fat, but the cookies still had plenty of calories; they just came from a different source.

At the same time that people increased their consumption of carbs, serving sizes were rising dramatically.

Mindy Hermann, a registered dietician in Mount Kisco, N.Y., says: "Everything is supersized. A single serving of a soft drink was once 6 ounces; today it is 20 ounces. A bagel no longer weighs 2 ounces; it weighs 4 or 6. Hamburgers come in double and triple sizes with two buns, twice as much cheese and a high-calorie sauce."